Mechanism of Directional Energy Transfer and Synergistic Control of Dynamic Burden‐Blasting Effects in Underwater Hole‐by‐Hole Blasting in Complex Aquatic Environments

This study addresses the challenge of simultaneously controlling rock fragmentation and vibration during underwater rock blasting in complex environments. The Wuzhou Siliang River underwater blasting project was adopted as a case study. This research integrated field tests with LS‐DYNA numerical simulations based on the fluid–structure interaction (FSI) theory. Specifically, this study investigates the control mechanism by which hole‐by‐hole initiation (HBHI) regulates the directional transfer of explosive energy. Employing the control variable method, four distinct initiation schemes were designed, with the variables being initiation sequence (conventional sequence vs. fishbone sequence) and delay time (long delay: 2.5 ms for in‐hole delay and 5 ms for interhole delay; short delay: 1 ms for in‐hole delay and 2.5 ms for interhole delay). Meanwhile, other key blasting parameters, such as blast hole layout and charge structure, were kept consistent across all schemes to ensure the validity of comparative analysis. In the numerical model, the Holmquist–Johnson–Cook (HJC) constitutive model was employed to characterize the rock mass, whereas the Jones–Wilkins–Lee (JWL) equation of state was used for the explosive. Results demonstrate that, in comparison with conventional initiation schemes, the scheme integrating “short delay + fishbone initiation network + decked charging” achieves a 25% reduction in vibration peak and a 30% increase in the qualified fragment ratio (with fragment size ranging from 0.3 to 0.8 m), exhibiting a significant improvement in blasting performance. Additionally, this study indicates that the combination of “short delay + fishbone initiation network + decked charging” can enhance energy transfer efficiency. These findings provide technical support for optimizing parameters in related engineering projects.